Genetic variation of the ribosomal DNA intergenic spacer of maize

Four maize (Zea mays L.) populations selected for grain yield BS10, BS11, RBS10, and RSSSC, were assayed for molecular variation in the ribosomal DNA (rDNA) intergenic spacer (IGS) at initial and advanced cycles of selection. RSSSC and RBS10 underwent reciprocal recurrent selection with an inbred tester in a high yield environment, whereas BS10 and BS11 were subjected to full-sib reciprocal recurrent selection. Maize rDNA, is highly repetitive and shows IGS length variation within and among individuals. Five different ribosomal spacer length variants (rslvs) and a polymorphic SstI restriction site were detected in the four populations. The 5 rslvs and the polymorphic restriction fragment were observed in twenty different combinations, or hybridization fragment patterns (HP). RSSSC, RBS10, and BS11 showed significant changes in the overall rslv and HP frequencies between cycle 0 and the advanced cycle of selection, whereas BS10 did not. In general, two specific HPs were more frequent in the majority of the advanced cycles of the four populations. The frequency changes between initial and advanced cycles were more dramatic for HPs than rslvs. These results are consistent with earlier findings and further support the hypothesis that certain rDNA HPs may be responding to selection for grain yield and may be associated with a selective advantage in US Corn Belt environments.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Biology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Kaufman, Benjamin

Contributors dc:contributor

• Rocheford, Torbert R.

• Biology, Molecular
• Biology, Genetics

Statement dc:rights

• Copyright 1995 Kaufman, Benjamin

Language dc:language

eng

Identifier

AAI9543621
(UMI)AAI9543621

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/19268